Corrosion inhibitor

ABSTRACT

Iron surfaces are protected against corrosion by aqueous acidic solutions containing a polyhydric compound or derivative thereof by dispersing into the corrosive solution which will contact the metal surface an effective amount of a heterocyclic amine, an acetylenic alcohol and an ionizable iodine containing compound.

United States Patent 11 1 Griffin et a1.

CORROSION INHIBITOR Inventors: Thomas J. Griffin; Francis E.

Dollarhide, both of Tulsa, Okla.

Assignee: The Dow Chemical Company,

Midland, Mich.

Filed: Oct. 2, 1972 Appl. No.: 294,327

References Cited UNITED STATES PATENTS 9/1951 Malowan 252/392X 5/1955 Hager et al. 10/1963 Harrison ct a1. 252/148 1 June 11, 1974 3,161,598 12/1964 Geld t t 252/147 3,260,673 7/1966 Fisher 252/147 X 3,404,094 10/1968 Keeney 252/148 3,548,945 12/1970 Gidley 166/307 3.658.720 4/1972 McDougall et a1. 252/148 X 3,686,129 8/1972 Loucks 252/147 Primary ExaminerLeon D. Rosd-ol Assistant ExaminerHarris A. Pitlick Attorney, Agent, or FirmBruce M. Kanuch [5 7 ABSTRACT Iron surfaces are protected against corrosion by aqueous acidic solutions containing a polyhydric compound or derivative thereof by dispersing into the corrosive solution which will contact the metal surface an effective amount of a heterocyclic amine, an acetylenic alcohol and an ionizable iodine containing compound.

6 Claims, N0 Drawings CORROSION INHIBITOR BACKGROUND OF THE INVENTION U.S. Pat. No. 3,107,221 teaches that a mixture of certain amines and acetylenic alcohols inhibit corrosion of metals in contact with corrosive acids such as HCI and/or HF. However, it has been found that these inhibitors are not effective to prevent corrosion of iron by corrosive acidic solutions containing a polyhydric compound or derivative thereof, e. g. glycols and glycol ethers.

This lack of protection is especially acute with iron containing alloying amounts of such metals as chromium, nickel and the like. These iron alloys are employed to manufacture flexible oil well tubing and the like.

SUMMARY OF THE INVENTION Iron surfaces are protected against corrosion by acidic solutions containing a polyhydric compound or derivative thereof by dispersing into the corrosive solution an effective amount of a heterocyclic amine, e.g. pyridine, quinoline, etc., an acetylenic alcohol, and iodine anions.

The teachings of U.S. Pat. No. 3,107,221 are specifically incorporated herein by reference.

DETAILED DESCRIPTION OF THE INVENTION An essential constituent of the corrosion inhibitor formulation of the present invention is iodine anions. The iodine anions can be provided by organic and inorganic ionizable iodine compounds such as taught in U.S. Pat. No. 2,567,156, the teachings of which are specifically incorporated herein by reference. Included by way of example are alkaliand alkaline earth metal iodine compounds, e.g. potassium iodide, sodium iodide, potassium iodate, iodoacetic acid, ammonium iodide, hydrogen iodide, copper iodide, and the like. The particular source from which the iodine anions are derived is not critical to the practice of the invention. Iodine salts of the heterocyclic amines or acetylenic a1- cohols can be employed as both the source of the amine oralcohol and the iodine ions. An effective amount of the iodine compound is employed to decrease the corrosion rate of the metal to an acceptable level. As little as 0.0001 per cent by weight of the acidic solution of an iodine compound can be effective. The maximum amount is dictated by economic considerations. An acetylenic alcohol having the formula wherein each R represents hydrogen, a C to C alkyl alkynyl or alkyenyl radical, or a phenyl, substituted phenyl or hydroxyalkyl alkynyl or alkyenyl radical containing from 1 to 4 carbon atoms and the a Rs may be joined together to form a cyclohexyl ring is employed. Acetylenic alcohols which can be employed include mono and polyhydric compounds such as, for example, propargyl alcohol, 1,4-butynediol, ethynylcyclohexanol 3-methyl-l-nonyn-3-ol, 2-methyl-3-butyn-2-ol, a-ethynyl-2,4,6-trimethylbenzyl alcohol, 2methyl-lpentyn-3-ol, a-ethynylbenzyl alcohol and the like.

The heterocyclic amine which can be employed herein includes one-or more pyridine and quinoline compounds and/or derivatives thereof.

The pyridiens include pyridine and alkyl, alkynyl and alkyenyl derivatives wherein the carbon constituent can be C to C and can be branched or straight chained. Specific pyridines which can be employed include, for example, a mixture of alkyl pyridines having an average molecular weight of about 170.

Quinolines which can be employed are those compounds which are generally isolated from suitable coal tar distillates which have an appreciable concentration of oils boiling in the range of from about 235 to about 240 C. Compounds which are isolated in this manner include quinoline, 2-methylquinoline, 4-

methylquinoline, isoquinoline, 2,8-dimethylquinoline and the like. Generally, the pyridine and quinoline compounds are employed as complex mixtures containing several species of the compounds. Quaternary salts of both pyridine, quinoline and derivatives thereof can be employed. Also, mixtures of quinolines and pyridines are useful. Specific quinoline compounds which can be employed include N-benzolquinoline chloride; l-benzoyl-2-cyano-1,2-dihydroquinoline; 2- carboxyquinoline; 2-cyanoquinoline. Also alkyl quinoline; quinoline aldehydes; hydroquinolines, e.g. 1,2- dihydroquinoline; N-methyl-2-phenyll ,2- dihydroquinoline quinoline methiodide; l,2,3,4- tetrahydroquinoline; 6-nitrosotetrahydroquinoline; cis and trans decahydroquinoline; hydroxyquinolines such as 2 and 4-hydroxyquinolines; 3-carboxy4- hydroxyquinoline; 7'iodo-8-Ihydroxyquinoline-5- sulfonic acid; 5-chloro-7-iodo-8-hydroxyquinoline; the copper salt of 8-hydroxyquinoline; haloquinolines such as 2 and 4 chloroquinolines; 4,7-dichloroquinoline; ethyl-4-hydroxy-7-chloro3-quinoline carboxylate; 3- bromoquinoline; aminoquinolines such as 3- aminoquinoline; 4-aminoquinoline; 4- alkylaminoquinoline; 8-aminoquinoline; 6-methoxy-8- dialkylaminoalkylaminoquinoline; aldehydes; ketones and acids of quinoline such as 2 and 4 quinoline carboxaldehydes; quinaldaldehyde; 2-quinoline carboxylic acid; benzoquinolines such as benzo[f] quinoline; biquinoline; isoquinoline and the like.

In carrying out the present invention the constituents of the corrosion inhibitor are mixed with an aqueous solution of a mineral acid or with water which is thereafter mixed with the mineral acid. The inhibited acid solution may then be employed in oil well acidizing or industrial acid cleaning methods. The amine and acetylenic alcohol are employed in a volume ratio of about 9 to 1 to l to 9 amine to alcohol and employed in a total amount of from about 0.05 to about 1 per cent by volume of the acidic solution to be inhibited.

In a preferred manner of carrying out the present invention a heterocyclic amine, an iodine compound and an acetylenic alcohol are mixed together, in the range of ratios hereinbefore described, as an aqueous or hydrocarbon mixture, preferably with a surface active agent. The resulting mixture is agitated to assure complete distribution of the additives in the aqueous phase. Thereafter this mixture is mixed with an acidic solution to obtain an inhibited acid suitable for use in oil well acidizing or industrial acid cleaning methods.

Various types of surface-active agents have been found to be effective and useful in assuring the complete dispersion of the active ingredients throughout the composition and a better contact of the inhibitor with the metallic surface. In general, any surface-active agent that is stable in aqueous acid may be used. Thus, for example, one may employ from 0.05 to 2 per cent were placed in a four ounce, wide mouth bottle. An inhibitor to be tested was then mixed with the acid. After weighing the metal coupon it was placed in the acid solution. The test solution was then heated and the test by volume of an ionic or nonionic surface-active dis- 5 Coupons p in Contact With the acid Solution for persing agent, such as an oxyethylated alkylphenol, amabout 4 hours at a temperature of C and 1000 P monium alkylbenzene-parasulfonate, dioctyl sodium C for 16 hours at p Pressure The metal sulfosuccinate, or trimethylstearylammonium chloride. Coupon was removed from the acid solutlohet the end of the test period, cleaned, dried and reweighed. The Various c d c Solutions n ning. in addition. a corrosion rate was then calculated and set forth as the polyhydric compound have been foun to be effecloss of metal in lbs/sq. ft. The various inhibitor solut y inhibited against metal Corrosion y the p ytions tested are set forth in the following Table l. The them Of the Compositions of the Present mVehtlOhcorrosion test data are set forth'in Table 11. The acid Thus, mineral acids such as sulfuric, phosphoric, acetic di consisted f a mixt f 90 parts by volume and hydrochloric acids and the like may be effectively of a per cent by weight HCl solution and 10 parts by inhibited by employing the principles of the present inl e of ethylene glycol monobutyl ether. vention. TABLE I Polyhydric compounds are employed in acidic solulnhlbltor rmulauons Inhibitor Code Composition Per Cent by Weight tions for various purposes. For example, in U.S. Pat. No. 3,548,945 glycol ethers are employed in conjuncv y g tionwith aqueous acid solutions to acidize siliceous forlfy f fs isl f :5 mations. The teachings of the patent are specifically inl y p filhylcne Oxide 7 1 Z! l corporated herein by reference. It is these types of ulkyll'gyridine chlorides aqueous acidic solutions which were found to be corro- B glkylquinolinium chlflrklie lit-3 Y ame as A. except a 'y pyridine sive even in the presence of amine-acetylenic alcohol chloride and alkylquimlinium inhibitors which are taught in U.S. Pat. No. 3,107,221. chloride obtained from The present invention overcomes this problem through C. 23i? mmmercal 560 the discovery that the effectiveness of these inhibitors Surfactant 7.5 is substantially increased by including in addition an iogggg a l s z dine ion. Thus, acidic aqueous solutions containing D. kerosene 5&0 surfactant 7.5 polyhydric compounds such as glycols, e.g. polyglycols, isopmpyl alcohol m ethylene glycol, glycol ethers or glycol esters, such as alkylpyridine 16.3 taught in U.S. Pat. No. 3,548,945, at col. 2, line 62 E :Lgjgggg 5 through col. 3, line 2, can be inhibited by practicing the surfactant 7:5 isopropyl alcohol 7.0 principles of the present invent on. v dodecyl amine 23'0 propargyl alcohol 6.5 The inhibitors of the present invention are unique in F. kerosene 56.0 surfactant 7.5 that they are operable when employed at both low tem- 40 isopmpyl alcohol 7'0 peratures and at temperatures as high as about 275 F. propargyl alcohol 295 TABLE 11 Concentration Corrosion rate percent lbs/sq. ft., by wt. of iron sample Test acid No. Inhibitor solution Salt and concentration Temp C 1 2 l A 1.5 KI (one lb. per 1 gal. of inhibitor) 250 0.038 0.019 2 B 0.1 KI (one lb. per 1000 gal. of acid 301.). 120 0.0074 0.0054 3 C 0.1 Kl (one lb. per 1000 gal. of acid sol.). 120 0.024 0.030 4 D 0.1 Kl (one lb. per 1000 gal. of acid sol). 120 0.016 0.014 5 E 0.1 Kl (one lb. per 1000 gal. of acid sol.). 120 0.013 0.013 6 E 1.5 Kl (15 lbs. per 1000 gals. acid) 250 0.45 0.57 7 F 0.1 KI (one lb. per one gal. of acid)..... 120 0.018 0.011 8 A 1.5 liege 250 0.17 9 A l N213PO4 lb. per 1000 gal. of acid). 250 0.33 10..... A l Net- 3401 (25 lb. per 1000 gal. of acid) 250 0.30

EXAMPLE An acceptable corrosion standard set for the iron sample No. l is less than 0.05 lb/sq. ft. at a temperature of 250 C; .02 lb/sq. ft. at a temperature of about 200 C and 0.01 lb/sq. ft. at a temperature of about C. For iron sample No. 2 the acceptable corrosion rate is established to be about one half of that for sample No.

What is claimed is: 1. An acidic solution inhibited to corrosion of metal which consists essentially of:

a an acid selected from the group consisting of HCl, sulfuric, phosphoric, acetic, hydrofluoric, formic,

propionic and mixtures thereof,

b an acetylenic alcohol,

c a heterocyclic amine,

d an ionizable iodine compound, and

e a water soluble polyhydric organic compound, said amine and alcohol making up from about 0.05 to about 1 per cent by weight of the composition, and further wherein said amine and said alcohol being present in said composition in a volume ratio of amine to alcohol ranging from about 9 to l to about 1 to 9, said ionizable iodine compound being present in an amount of at least about 0.0001 per cent of said composition, further wherein said polyhydric compound is a glycol, or a glycol ether present in an amount ranging from about 2 to about 25 per cent by volume of said acid, said acetylenic alcohol has the formula wherein each R represents hydrogen, a C to C alkyl, alkynyl or alkyenyl group, a phenyl or substituted phenyl group, or a hydroxyl C to C alkyl, alkynyl or alkyenyl group wherein the a Rs may be joined together to form a cyclohexyl group, and the heterocyclic amine is pyridine or its alkyl, alkenyl or alkynyl derivatives wherein the carbon constituent can be C to C or a--. quinoline compound.

2. The composition of claim 1 wherein said ionizable iodine compound is an alkali or alkaline earth metal iodine containing compound.

3. The composition of claim 1 wherein said polyhydric compound is a glycol ether.

4. The composition of claim 1 wherein said polyhydric compound is a glycol.

5. The composition of claim 1 wherein the heterocyclic amine is selected from the group consisting of pyridine, alkyl, alkynyl or alkyenyl pyridines wherein the carbon constituent contains C. to C or quinoline; 2- methyl quinoline; 4-methyl quinoline; isoquinoline; 2,8-dimethyl quinoline; N-benzol quinoline chloride; l-benzoyl-2-cyano-l,2-dihydro quinoline; Z-carboxy quinoline; 2-cyano quinoline; l,2-dihydro quinoline; N-methyl-Z-phenyl-l,2-dihydro quinoline; quinoline methiodide; l,2,3,4-tetra-hydro quinoline; 6- nitrosotetrahydro quinoline; cis and trans decahydro quinoline; 2 and 4-hydroxy quinoline; 3-carboxy-4- hydroxy quinoline; 7-iodo-8-hydroxy quinoline-5- sulfonic acid; 5-chloro-7-iodo-8-hydroxy quinoline; the copper salt of 8-hydroxy quinoline; 2 and 4 chloro quinolines; 4,7-dichloro quinoline; ethyl-4-hydroxy-7- chloro-3-quinoline carboxylate; 3-bromoquinoline; 3- aminoquinoline; 4-aminoq uinoline; 4- alkylaminoquinoline; 8-aminoquinoline; 6-methoxy-8- dialkylaminoalkylaminoquinoline; 2 and 4 quinoline carboxyaldehyde; quinaldehyde; 2-quinoline carboxylic acid; benzo quinoline; biquinoline; and mixtures of such heterocyclic amines.

6. A method of cleaning iron surfaces which comprises contacting said surface with an acidic solution as defined in claim 1. 

2. The composition of claim 1 wherein said ionizable iodine compound is an alkali or alkaline earth metal iodine containing compound.
 3. The composition of claim 1 wherein said polyhydric compound is a glycol ether.
 4. The composition of claim 1 wherein said polyhydric compound is a glycol.
 5. The composition of claim 1 wherein the heterocyclic amine is selected from the group consisting of pyridine, alkyl, alkynyl or alkyenyl pyridines wherein the carbon constituent contains C1 to C15 or quinoline; 2-methyl quinoline; 4-methyl quinoline; isoquinoline; 2,8-dimethyl quinoline; N-benzol quinoline chloride; 1-benzoyl-2-cyano-1,2-dihydro quinoline; 2-carboxy quinoline; 2-cyano quinoline; 1,2-dihydro quinoline; N-methyl-2-phenyl-1,2-dihydro quinoline; quinoline methiodide; 1,2,3,4-tetra-hydro quinoline; 6-nitrosotetrahydro quinoline; cis and trans decahydro quinoline; 2 and 4-hydroxy quinoline; 3-carboxy-4-hydroxy quinoline; 7-iodo-8-hydroxy quinoline-5-sulfonic acid; 5-chloro-7-iodo-8-hydroxy quinoline; the copper salt of 8-hydroxy quinoline; 2 and 4 chloro quinolines; 4,7-dichloro quinoline; ethyl-4-hydroxy-7-chloro-3-quinoline carboxylate; 3-bromoquinoline; 3-aminoquinoline; 4-aminoquinoline; 4-alkylaminoquinoline; 8-aminoquinoline; 6-methoxy-8-dialkylaminoalkylaminoquinoline; 2 and 4 quinoline carboxyaldehyde; quinaldehyde; 2-quinoline carboxylic acid; benzo quinoline; biquinoline; and mixtures of such heterocyclic amines.
 6. A method of cleaniNg iron surfaces which comprises contacting said surface with an acidic solution as defined in claim
 1. 